When the grub splash screen is displayed press the 'Esc' key. Select the Linux (CentOS5) boot choice and press the 'e' key. Select the kernel line and press the 'e' key again, at the end of the line add a space followed by the number three (3). When done press the enter key followed by the 'b' key, when the system is done booting log on as root and type;
rpm -Uhv
http://apt.sw.be/packages/rpmforge-r...l5.rf.i386.rpm
yum install nvidia-x11-drv
system-config-display --reconfig --set-depth=24 --set-driver=nivida
Reboot the system by pressing the three key combo of Ctrl+Alt+Del